Dark Energy and EM/G unification.

What is the consensus out there on Dark Energy? Do we believe it exists or is it just a number that shows us how much our current calculations are off by?

If we were to unify EM and G, would getting rid of Dark Energy be a postulate for such a theory?

One could for example think of EM as being G, but at long ranges we imagine that the electron "disappears" (IE the electron's ability to interact with a proton goes down by E as the distance goes up) and so at large distances we are left with protons pushing each other away (The protons ability to interact with eachother goes down with a number P which is lower than E).

Tweak the numbers so to speak and you can build a system which explains expansion while still being operational as it is today on a planet. It might even be possible to tune the numbers to show that the attraction of gravity in a "small system" like the earth is simply a result of the uneven E/P strengths.

Has there been any calculations done which goes down this path? Without going into the actual math itself (which would be way above me), I'm wondering if the numbers pan out, and If they do, what are the arguments against such a view of the universe?